Spray gun



3, 1965 J- E. ULLMAN 3,198,435

SPRAY GUN Filed June 21, 1963 I 2 Sheets-Sheet 1 lNVE/VTOR 99b 99 JOHN E.ULL1'1AN ATTORNEY United States Patent Office Patented Aug, 3, 1965 3,198,435 SPRAY GUN John E. Ullrnan, Huntingdon Valley, Pa, assignor to Huntingdon industries Incorporated, Bethayres, Pan, a corporation of Pennsylvania Filed June 21, 1963, Ser. No. 289,704 6 Claims. (Cl. 239-117) This invention relates. to improvements in a spray gun, and more particularly concerns a spray gun especially adapted for spraying adhesive on thefi'aps of a carton, such as is shown in co-pending patent application Serial No. 150,817, filed November 7, 1961, now Pateht'No. 3,152,923, by Edward E. Marshall and John E. Ullman.

It has long been desired to provide a spray gun which could be substituted for the conventional roller adhesive apparatus in a carton, or case, sealer. A case sealer is a machine for ad-hesively sealing the flaps of a corrugated paper carton which contains, for example, twelve or twenty-four cans.

Heretofore, it has been suggested to utilize a single adhesive spray gun to spray adhesive on the flap of a carton. However, in order to cover a sufiicient area of the flap to insure sealing, the spray gun had to be placed a considerable distance from the flap. This presented some difi'iculty in that the spray area was difficult to control, and a considerable amount of adhesive was lost through overspraying. Moreover, the overspray settled on adjacent parts of the machine and there congealed, and thereby created a messy maintenance problem.

It is an object of the present invention to overcome the aforementioned problems, and to provide a spray gun which sprays adhesive on the flap of a carton in a sharp, easily controlled pattern.

It is another object to provide a spray gun which gives a wide, uniform, and well defined spray pattern to the flap of a carton.

It is another object of this invention to provide a spray gun which is adapted to spray a pattern of parallel stripes of adhesive on the flaps of a carton, the number of stripes being varied as desired.

Other objects and advantages of the invention, including its simplicity and economy, as well as the ease with which it may be adapted to existing equipment, will further become apparent hereinafter and in the drawings, in which:

FIG. 1 is a view in vertical section of a spray gun constructed in accordance with this invention and showing a removable selector tab in position;

FIG. 2 is a view in front elevation of the spray gun of FIG. 1, but with needle collars shown in place of the selector tabs;

FIG. 3 is a view in top plan of a selector tab which forms an element of the invention; and

FIG. 4 is a side view of the selector tab of FIG. 3.

Although specific terms are used in the following description for clarity, these terms are intended to refer only to the structure shown in the drawings and are not intended to define or limit the scope of the invention.

Turning now to the specific embodiment of the invention selected for illustration in the drawings, there is shown a spray gun which includes a housing 61 adapted to be mounted in close proximity to a flap of a carton and having a cylinder 62 formed therein, a piston 63 having a piston head 64 positioned in cylinder 62 and a piston rod 65 extending upwardly therefrom, a needle bar 66 mounted on the top of piston rod 65 and adapted to be reciprocated thereby, a spray head 67 mounted on housing 61 above needle bar 66 and having a plurality of adhesive spray orifices 68, and a longitudinally movable needle 71 extending from each adhesive orifice 68 and operatively connected to needle bar 66.

Piston head 64 is double acting and is provided with sides 72, .73. Compressed air from a gun control valve (not shown) may be connected to exert pressure on side '73 of piston head 64 in the spray gun by connecting an air conduit 38 to a port 74 formed in cylinder body cap 75 which is mounted on the bottom of cylinder housing 61. Compressed air from a gun control valve may be connected to side 72 of piston head 64 by connecting an air conduit to port 76 which is formed in housing 61.

An Oring 77 provides a seal between housing 61 and cylinder body cap 75, and O-ring 78 is mounted in a groove 81 in piston head 64 to provide a seal between side 72 and side 73 of piston head 64.

,Piston rod is centered in a guide liner 82 mounted in an opening 83 in housing 61, and an O-ring 84 provides a seal between piston rod 65 and guide liner 82. A dirt seal 85 is mounted in opening 83 above guide liner 82.

Compressed air impinging againstside 72 of piston head 64 moves it away from adhesive discharge orifices 68, and piston rod 65 moves needle bar 66 and the needles 71 in the same direction to move the tip of the needles out of the adhesive discharge orifices 68. 1

On the other hand, the impinging of compressed air against side 73 of piston head 64 moves the piston head 64 in the direction toward adhesive discharge orifices 68 and thereby moves needle bar 66 andneedles 71 toward adhesive discharge orifices 68 to move the tips'of needles 71 into orifices 68 to stop the discharge of adhesive therefrom.

The top of piston rod 65 is received in an opening in a lower horizontal member 86 of needle bar 66, and is held tightly therein by a socket pipe plug 87.

Needles 71 are provided with a tip 88, a shaft a head 92. Head 92 is received in a space in needlebar 66 between lower horizontal member 86 and upper horizontal member 93 which is provided with slots 94 that receive shafts 91 but do not pass needle heads 92.

Removable selector tabs 99 are provided and are adapted to be positioned between needle bar upper horizontal member 93 and needle heads 92 so that movement of bar 66 is transmitted to needle heads 92 to move needles 71 and their tips 88 in and out of their orifices 68. A pattern of any desired number of stripestfrom none to four in the spray gun herein used to illustrate the invention) of adhesive may be sprayed on the flaps of a carton by simply choosing the number of selector tabs 99 to be used.

Needle heads 92 are spaced away from upper horizontal member 93 of needle bar 66 in the direction away from orifices 68 by a distance greater than the length of the operating stroke of needle bar 66, so that the movement of bar 66 is not transmitted to needle heads 92 when selector tabs 99 have been withdrawn from their position between heads 92 and member 93.

When a spray gun is used in an operation wherein it is never desired to shut oif any of the spray orifices, needle collars 100 may be substituted for selector tabs 99 in the assembly of the unit.

Referring now more particularly to FIGS. '3 and 4, selector tab 99 is preferably made of a resilient material and includes a squared-off end 99a which abuts needle bar 66 so as to prevent rotational movement of tab 99 about needle shaft 91. A slot 99b is formed in tab 99 and has flared shoulders 99c which guide needle shaft 91 into slot 9% more easily. A rounded, enlarged portion 99d receives needle shaft 91 and snaps around it to hold tab 99 in place. Finger grips 99e assist the operator in inserting or withdrawing tab 99 from its position between needle heads 92 and member 93. 7

Each needle head 92 is supported by a spring assembly which presses upwardly to insure that tip 88 of needle 71 is seated properly in orifice 68 ofadhesive discharge 91, and

nozzle 96, despite any manufacturing variations of the dimensions of tips 88 or the adhesive discharge orifices 68.

Spray head 67 includes a base 97 which is bolted to a cap 98. A nozzle 101 is seated in an opening in cap 98 and forms an annular air discharge orifice 102 around the tip of adhesive discharge orifice 68. Atomizing air may be connected into annular air discharge orifice 102 from an atomizing air valve (not shown) through an air conduit into an air passage 103 formed in base 97. Air passages 104 in cap 98 connect air passage 103 to the annular air discharge orifice 102.

An adhesive chamber 105 is formed in base 97 and is connected to the interior of adhesive discharge nozzle 96 and to adhesive discharge orifice 68. Adhesive may be connected into adhesive chamber 105 from a glue pot (not shown) by means of a glue conduit.

To prevent adhesive from seeping out along the shaft 91 of needle 71, packing 106 is positioned around shaft 91 and is held in place by a packing nut 107. When tab 99 is removed, the friction of packing 106 against shaft 91 of needle 71 is sufiicient to maintain the needle seated against the force of the liquid pressure in spray head 67, and against gravity if the spray gun is mounted pointing upwardly.

It is to be noted that spray head 67 and needles 71 may be removed from housing 61 and replaced as a unit by unscrewing bolts 108 and sliding the needles 71 out of the slots 94 in the upper horizontal member 93 of needle bar 66. This easy removal as a unit for inspection, cleaning, and repair is one of the outstanding advantages of the invention.

In operation, piston head 64 is moved away from adhesive discharge orifices 68 by the operation of a gun control valve sending compressed air through an air con- .duit to impinge against side 72 of piston head 64. Piston 63 moves needle bar 66 and needles 71 away from orifices 68, when selector tabs 99 are in position between upper horizontal member 93 and needle heads 92, to withdraw needle tips 88 therefrom, and the atomizing air from annular orifices 102 impinges against the adhesive being discharged from orifices 68 and carries the adhesive to the surface of the carton flap. Then the gun control valve is actuated to send compressed air through an air conduit to impinge against the side 73 of piston head 64 to move piston 63, needle bar 66, and needles 71 toward orifices 68 to close orifices 68 by inserting the tips 88 of needles 71 therein.

The carton flap is moved relative to the tip of the spray gun during the spraying operation so that the flap receives stripes of adhesives. Such stripes may overlap to form a band.

The present invention provides a number of advantages over the prior art. It uses a lesser quantity of adhesives, it reduces the time required to compress and seal the glued flap, and it requires less maintenance than roll type adhesive applicators. Instead of applying a gummy, layer, which is thicker than needed for eifective sealing, the present invention sprays on a controlled mist of tiny droplets which saves material, dries faster, and reduces compression time. Messy maintenance problems that go with rollers and glue pots are eliminated.

The specially designed spray heads with their multiple orifices deposit the adhesive on the carton flap and prevent overspray.

The present invention provides precise control of the adhesive coverage. The multiple orifice spray head may be positioned as close to the carton flap as required to achieve precise control, not only of adhesive thickness, but also of adhesive pattern. For example, the spray head may be positioned to spray a broad band of adhesive for maximum flap coverage, or it may be positioned so as to spray thin stripes of controlled width on the flap when less coverage is desired.

Another advantage of the present invention is that the removableselector tabs 99 provide for tie-activating all or any number of the spray orifices of the gun. Accordingly, the gun is adapted to spray a varied pattern of any desired number of stripes of adhesive by simply choosing the number and location of the selector tabs to be used (the outer orifices, or the inner orifices, or alternate orifices, for example, may be chosen as the operative ones).

The present invention is easily adapted to new or existing machines. It is not necessary to remove the roller type applicators when installing the spray kit of the present invention on conventional case sealers. The spray kit of the present invention functions with either resin or dextrin adhesives or any sprayable adhesive.

It is to be understood that the form of the invention herewith shown and described is to be taken as a presently preferred embodiment. Various changes may be made in the shape, size and arrangement of parts. For example, equivalent elements may be substituted for those illustrated and described herein, parts may be reversed, and certain features of the invention may be utilized independently of the use of other features, all without departing from the spirit or scope of the invention as defined in the subjoined claims.

The claimed invention:

1. A spray gun for spraying adhesive on the flaps of a carton comprising a housing adapted to be mounted in close proximity to a flap of a carton and having a cylinder formed therein, a piston having a piston head positioned in said cylinder and a piston rod extending therefrom, a needle bar connected to said piston rod and reciprocable thereby, a spray head mounted on said housing and containing a plurality of adhesive spray orifices, a longitudinally-movable needle extending from each of said orfices and including a shaft with a tip at one end and a head at the other, said head being spaced away from said needle bar in the direction away from said orifices a distance greater than the length of the operating stroke of the needle bar so that the movement of the needle bar is not transmitted directly to the needle heads, and a removable selector tab positioned between the needle bar and one of the needle heads so that the movement of the needle bar is transmitted to the needle head to move the needle and its tip in and out of its adhesive spray orifice, whereby said spray gun is adapted to spray a pattern of a desired number of stripes of adhesive on the flaps of the carton by choosing the number of said tabs to be used.

2. The spray gun defined in claim 1, wherein said selector tab is made of a resilient material and includes a squared-off end which abuts said needle bar so as to prevent rotational movement of said tab about the needle shaft, said tab having a slot formed therein having flared shoulders which guide said needle shaft into said slot, a rounded, enlarged portion of said slot which receives the needle shaft and snaps around it to hold said tab in place, and finger grips on said tab which assist in inserting and withdrawing said tab from its position between said needle head and said needle bar.

3. The spray gun defined in claim 1, wherein said piston is provided with a double acting piston head, whereby air means may be connected to one side of said piston head to move it away from said adhesive spray orifices and thereby move said needle bar to move said needles out of. said orifices, and air means may be connected to the other side of said piston head to move it toward said orifices and thereby move said needle bar to move said needles into said orifices.

4. A spray gun for spraying adhesive on the flaps of the carton comprising a housing adapted to be mounted in close proximity to a flap of a carton and having a cylinder formed therein, a piston having a piston head positioned in said cylinder and a piston rod extending therefrom, a needle bar connected to said piston rod and reciprocable thereby, a spray head detachably mounted on said housing and having a plurality of adhesive spray orifices contained therein, a longitudinally movable needle extending from each of said orifices, said needle bar having a lower horizontal member connected to said piston rod and having an upper horizontal member with slots formed therein, each of said needles having a tip which seats in its orifice, a shaft which is received in one of said slots, and a head which is received in a space between the upper and lower horizontal members of said needle bar and is too large to pass through said slots, said needle head being spaced away from said upper horizontal member a distance greater than the operating stroke of the needle bar so that the movement of the needle bar is not directly transmitted to the needle heads, and a removable selector tab positioned between the needle bar upper horizontal member and one of the needle heads so that movement of the needle bar is transmitted to the needle head to move the needle and its tip in and out of its adhesive spray orifice, whereby said spray gun is adapted to spray a pattern of one to four stripes of adhesive on the flaps of the carton.

5. A spray gun for spraying adhesive on the flaps of a carton comprising a housing adapted to be mounted in close proximity to a flap of a carton and having a cylinder formed therein, a piston having a piston head positioned in said cylinder and a piston rod extending therefrom, a spray head mounted on said housing and including a cap bolted to a base, a plurality of adhesive-spray orifices contained in said cap, a single adhesive chamber formed in said base and connected to' each adhesivespray orifice by passages formed in said spray head, an atomizing-air orifice positioned around each adhesivespray orifice, an air passage formed in said base and connected to said atomizing-air orifices by air passages formed in said cap, a needle bar connected to said piston rod and reciprocable thereby, a longitudinally movable needle extending from each of said adhesive-spray orifices and including a shaft with a tip at one end and a head at the other, said head being spaced away from said needle bar in the direction away from said orifices a distance greater than the length of the operating stroke of the needle bar, and a removable selector tab positioned between each needle head and the needle bar so that movement of the needle bar is transmitted to the needle heads to move the needle tips in and out of the spray orifices, said spray head and needles being easily removable as a unit from said housing for maintenance or repair.

6. A spray gun for spraying adhesive on the flaps of a carton comprising a housing adapted to be mounted in close proximity to a flap of a carton and having a cylinder formed therein, a piston having a piston head positioned in said cylinder and a piston rod extending therefrom, a spray head bolted on said housing and including a cap bolted to a base, a plurality of adhesive-spray orifices contained in said cap, a single adhesive chamber formed in said base and connected to each adhesive-spray orifice by passages formed in said spray head, an atomizing-air orifice positioned around each adhesive-spray ori-,

fice, an air passage formed in said base and connected to said atomizing-air orifices by air passages formed in said cap, an air conduit connecting said atomizing-air valve to said spray gun so that the gun may be located at a point remote from the atomizing-air valve, a needle bar connected to said piston rod and reciprocable thereby, and a longitudinally movable needle extending from each of said adhesive spray orifices and operatively connected to said needle bar, said needle bar having a lower horizontal member connected to said piston rod and having an upper horizontal member with slots formed therein, each of said needles having a tip which seats in its orifice, a shaft which is received in one of said slots, and a head which is received in a space between the upper and lower horizontal members of said needle bar and is too large to pass through said slots, said needle head being spaced away from said needle bar in the direction away from said orifices a distance greater than the length of the operating stroke of the needle bar, a removable selector tab positioned between each needle head and the needle bar so that movement of the needle bar is transmitted to the needle heads to move the needle tips in and out of the spray orifices, and a spring assembly supporting each needle head and mounted on said lower horizontal member of the needle bar, said spring assembly pressing upwardly against the needle head to insure that the needle tip is seated properly in its orifice despite any manufacturing variations in the dimensions of needle tips and orifices, said spray head and needles being easily removable as a unit from said housing for maintenance and repair by unbolting said head from said housing and sliding the needles out of the slots in said needle bar, said spray head being easily disassembled for cleaning by unbolting the cap from the base.

References Cited by the Examiner 11/35 Great Britain.

EVERETT W. KIRBY, Primary Examiner. 

1. A SPRAY GUN FOR ADHESIVE ONT HE FLAPS OF A CARTON COMPRISING A HOUSING ADAPTED TO BE MOUNTED IN CLOSE PROXIMITY TO A FLAP OF A CARTON AND HAVING A CYLINDER FORMED THEREIN, A PISTON HAVING A PISTON HEAD POSITIONED IN SAID CYLINDER AND A PISTON ROD EXTENDING THEREFROM, A NEEDLE BAR CONNECTED TO SAID PISTON ROD ANUD RECIPROCABLE THEREBY, A SPRAY HEAD MOUNTED ON SAID HOUSING AND CONTAINING A PLURALITY OF ADHESIVE SPRAY ORIFICES, A LONGITUDINALLY MOVABLE NEEDLE EXTENDING FROM EACH OF SAID ORIFICES AND INCLUDING A SHAFT WITH A TIP AT ONE END AND A HEAD AT THE OTHER, SAID HEAD BEING SPACED AWAY FROM SAID NEEDLE BAR IN THE DIRECTION AWAY FROM SAID ORIFICES A DISTANCE GREATER THAN THE LENGTH OF THE OPERATING STROKE OF THE NEEDLE BAR SO THAT THE MOVEMENT OF THE NEEDLE BAR IS NOT 